Thx Ann-Sofie, I found the file - very good documentation!.  Unfortunately the SN Swivel seems to be different. I cannot see the inner plastic-tube, also the two other parts look different.

does anyone know if the SN swivel (1995) has an inner plastic tube or bearings? It seems to me that there are only two parts, an inner part that just slides on the foil and an outer part with bearings between inner and outer part.

@Danny: thx for the hint, will wash it with fresh-water. 

herbert